Internal lapping machine



Dec. 15, 1931. H 5 ND E INTERNAL LAPPING MACHINE Filed June 6, 1927 6 Sheets-Sheet l H. S. INDGE Dec; 15, 1931.

INTERNAL LAPPING MACHINE 6 Sheets-Sheet 3 Filed June 6, 1927 172:)? 20% .l eriewz J. 15x9 2 A47 WMWS Dec. 15, 1931. H, 5 lNDGE 1,836,121

INTERNAL LA PPING MACHINE Filed June 6, 1927 6 Sheets-Sheet 4 Deb. 15, 1931.' s, [NDGE 1,836,121 I INTERNAL LAPPING MACHINE Filed June 6, 1927 6 Sheets-Sheet 5 Patented Dec. 15, 1931 UNITED STATES PATENT OFFICE HERBERT STUART INDGE, OF WESTBORO, MASSACHUSETTS, ASSIGNOR, BY MESNE AS- SIGNMENTS, TO NORTON COMPANY, OF WORCESTER, MASSACHUSETTS, A CORPORA- TION OF MASSACHUSETTS INTERNAL LAPPING meme Application filed June 6,1927. Serial No. 196,947.

This invention relates to a machine for lapping or honing internal surfaces such as the inner walls of rings, collars or bearings. It is an important object of my invention to provide a machine'for such purposes in which a rotatable lap may be caused to repeatedly traverse an internal surface axially, preferably while yieldingly engaged therewith.

Another. object is to provide a machine in which the lapping operation will be automatically discontinued after a predetermined number of axial traverses of the lap over the internal surface.

A further object of the invention is to provide means for presenting a new piece of work in position for lapping, such presentation being also preferably automatic.

Important features of the invention relate to the provision of a work holder which will align itself with the rotating lap, and to the provision of an improved form of lap which automatically expands tothe size of the hole to be lapped but which may be quickly and easily contracted for removal or' insertion in the work.

My invention further relates to arrangements and combinations of parts which will be hereinafter set forth and more particularly pointed out in the appended claims.

- A preferred form of the invention is shown in the drawings in which Fig. 1 is a side elevation of my improved lapping machine, with certain partsshown in section; I

Fig. 2 is a front elevation thereof;

Fig. 3 is an enlarged sectional side elevation of the lower portion of the machine,

- showing the driving mechanism;

Fig. 4 is a similar view of the upper por-.

Fig. 8 is a SiInilar View, showing the a expanded;

Fig. 9 is a sectional plan view, showing a slightly modified construction; Fig. 10 is a plan view of the upper end of the lapping elements, with, the expansion rod or plunger shown in section sleeve;

Fig. 12 is a detail sectional elevation, taken along the line 1212 in Fig. 6;

Fig. 13 is a partial front elevation, partly in section, showing the lapping head and the mechanism for contracting and expanding the lap;

Fig. 14 is a front elevation of the mechanism for raising and lowering the work table;

Fig. 15 is a sectional plan view of the intermittent table feed, taken along the line 15-15 in Fig. 3;

Fig-16 is a; sectional rear elevation of the mechanism for controlling the duration of the lapping -operation, taken along the line 1616 in Figs. 3 and '4;

Fig. 17 is a view similar to Fig. 16 but showing the parts in a different position;

Fig. 18 is a sectional rear elevation of certain clutch mechanism, taken along the line 1818 in Fig. 3; and

Figs. 19 and 20 are similar views, showing the operation of certain parts of the clutch.

Referring to the drawings, I have shown a lapping machine comprising a frame (Fig. 1) having a horizontal work table ro- Fig. 11 is a side elevation of the lap driving tatable in a guard or casing 31 and having a lapping head vertically reciprocated within a casing 32 secured to a standard 33 forming an upper portionof the frame 30.

A motor M is mounted on a bracket 34 projecting rearwardly from the frame 30, said motor being connected by a belt or chain 35 and pulley or sprocket 36 to a main drive shaft 37 rotatable in suitable bearings in the lower portion of the frame 30.

The work table 40 (Fig. 3) is normally maintained in raised or operative position, but mechanism is provided for intermittently lowering the table 40 and for intermittently. advancing the table angularly to present a new piece or pieces of work in posithe several mechanisms above outlined.

Lapping spindle and drive One or more lapping spindles Fig. 2) are mounted in bearings 51 and 52 Fig. 4) secured to the standard 33 of the frame 30. A bevel gear 53 is keyed to the central lower lapping spindle, but permits the spindle to slide freely therethrough. The gear 53 is engaged by a bevel pinion 54 secured to the front end of a cross shaft 55 supported in fixed bearings 56 and 57 in the standard 33 and having a pulley or sprocket 58 fixed to the rear end thereof and connected by a belt or chain 59 to a pulley or sprocket 60 on the drive shaft 37 (Fig. 3).- By these connections, the spindle 50 is continuously rotated.

If a plurality of spindles is used, a gear 61 (Figs. 4 and 13) is fixed on the spindle 50 and. engages similar gears 62 on the side spindles 50 and 50*, thus rotating the spin-- dles simultaneously. 1

A grooved collar .65 (Fig. 4) is fixed to the spindle 50 and is engaged by rolls 66 (Fig. 13) on the forked front end of a lever 67 (Fig. 4) pivoted on a stud 68 fixed in the standard If three spindles are used, additional collars (Fig. 13) are provided on the outer spindles and additional rolls 66 are provided on the outer faces of thelever 67 to engage the collars 65. The lever 67 is provided with a plurality of holes 69 and the standard 33is provided with corresponding holes, so that the stud 68 may be inserted in different positions to vary the proportions of the lever 67 and thus vary the reciprocation of the lapping spindle 50.

A link 70 is pivoted at 71 to the rear end of the lever 67 and is also pivoted at 72 on a within the standard 33. The gear 80 is engaged by a.pinion 82 on the cross shaft 55 previously described.

The slide plate 74 5) is mounted in suitable guide-ways 83 on the standard 33 and is vertically reciprocated by the connectionsv above described. Ordinarily the weights 75 are sufficient to somewhat overbalance the spindles 50 so that the upper rolls 77 continuously engages the rotating cam 78. If,

however, the spindles should overbalance the weights, or the slide plate should stick,'the

: lower roll 77 then becomes operative and the slide plate is similarly reciprocated under either condition. The cam 78 is so designed that the spindles will have a continuous reciprocation, without appreciable dwell; at the reversals, thus avoiding the production of bell-mounted holes.

Lap construction I have provided a special form of lap for use in my improved machine, involving important features of construction and operation which will now be described.

The lap is formed of a plurality of lapping elements 90 (Figs. 6 to 8), preferably three in number, which may be made by cutting a cylindrical or conical lap longitudinally into three pieces. The lower ends of the lap ping elements are reduced in diameter as in- 90 are provided with flanges 95 engaged by an internal annular flange 96 formed at the lower end of a cap or collar 97 threaded onto each lapping spindle 50, 50 or 50". Each flangedportion 95 of a lapping element is also provided with a slot or recess 98 adapted to receive a lug or projection 99 (Fig. 11) formed on thelower end of-a sleeve 100. i

-In assembling the parts, the lapping elements 90 are inserted from above in the circular opening 101 of the cap 97, and the sleeve 100 is then inserted in the opening cross shaft 73 (Fig. 5) which extends (101, with the projections 99 extending into through a slide plate 74. The ends of the shaft 73 extend at each side of the plate 74 and provide supports for weights 75 which counterbalance the spindles 50 where a plurality of spindles is used.

The slide plate 74 is provided with a pair of cam rolls 77 (Fig. 5) adapted to engage a cam 78, detachably connected by a stud 79 (Fig. 4) to a gear rotatable upon a fixed stud 81 projecting rearward from a support the slots 98, thus providing guides for the radial movement of the expanding lapping elements 90 and holding them in angularlv spaced relation. .The projections 99 are referably of greater length than the thic mess of the flanges .95. A second annular coil spring 102 may be provided near the upper ends of the lapping elements 90 to contract the samevas previously described.

On their inner surfaces, the lapping elements are provided with tapered or conical bearing surfaces 103 (Fig. 6) engaged by the tapered lower end 104 of an ex ansion rod or plunger 105 slidable longitudinally in an axial opening of the spindle 50. As the plunger 105 is pushed downward, the lapping elements 90 tend to expand against the ten-, sion of the annular springs 93 and 102.

At the upper end of each spindle 50, 50*. or 50 (Fig. 4) each plunger 105 extends through a forked lever 106 and is threaded to receive lock nuts 107 forming a shoulder or abutment for said lever. The levers are mounted on fixed pivots 108 in the standard 33 and are intermittently lifted by operating mechanism to be described.

A coil spring 110 is mounted on the upper end of each plunger 105 and is positioned between a washer 112 and pin 113 on the plunger 105 and a cap 114 threaded or otherwise secured on the upper end of the spindle 50. The spring thus acts to yieldingly force the plunger 105 downward and is of sufficient strength to overcome the tension of the annular springs 93 and 102. Each spring 110 may be adjusted by screwing its cap 114 on or off of the end of its spindle 50.

In Fig. 9 I have shown a slight modification in which the lower end of the plunger 105 is of triangular tapered cross section, as indicated at 115, and the lapping elements 116 are provided with similar flat inclined surfaces 117. The operation is substantially the same as that above described, except that relative angular movement of the plunger 105 and lapping elements 116 is prevented.

It will be noted, that inasmuch as the laps are expanded by acam or wedge of comparatively slight taper, the spring is able to push the laps are so guided and expanded as to partake of a strictly ,radial movement, during which all parts of each lap maintain parallelism with the remaining laps.

Work holders and table I have provided .speci'al work holders mounted on the work table 40 and adapted to freely align themselves with the rotating lap.

A preferred construction of the work holders is shown in Fig. 3, in which the work W is secured by clamping plates 120 in a ring or holder 121 which is provided with studs or trunnions 122 pivoted in lugs 123'extend/ ing upward from a base or stand 124 adapte to be clamped or otherwise secured to the work table 40. The ring or holder 121 is free to slide transversely along the axis of its trunnions 122 and is also free to rock on said trunnions. As the lap descends, it moves upper end of a supporting rod 125 slidable in abearing 126 in'the frame 30. The work table is also provided with edge recesses 127 adapted to receive a guide-roll 128 mounted on the casing 31, said roll accurately positioning the table angularly and holding the table from angular movement during the lapping operation. When the table is lowered, as will be hereinafter described, the recesses 127 are below the roll 128, thus permitting free rotation of the table.

A cam roll 130 (Figs. 3 and 14) is pivoted in a member 131 mounted on a stud 132 rotatably seated in an axial recess in the lower end of the supporting rod 125. The cam roll 130 is engaged by a cam 133 mounted on a cross shaft 134 rotatable in bearings in the lower part of the frame 30 and having a bevel gear 135 engaging a second bevel gear 136 fixed to the lower end of an upright shaft 137, also rotatable in fixed bearings in 'the' frame 30.

The shaft 137 is connected by'bevel gears 138 and 139 to a horizontal cross shaft 140 rotatable in fixed hearings in the base 30. The shaft=140 is interniittentlygiven a single revolution by clutch mechanism to be described and when thus actuated, the cam 133 is also given a single rotation, lowering the work table from operative position and thereafter raising the same to operative position.

Table feeding mechanism '15) enters the radial grooves or slots 143 in progressive order and each time advancing the work table 90, the action being'equivalent to the usual Geneva stop motion.

As the table is raised from its lower position, the roll 128 (Fig. 3) on the casing 31 enters one of the vertical slots 127 in the peripheryof the Work table and thus accurately centers the table and holds the same from rotation during the lapping operation.

Lap release mechanism Special devices are provided for allowing the lapping elements 90 to contract before the work table 40 is lowered and permitting them to remain contracted until the table is returned to its operative or raised position. For this purpose the levers 106 (Fig. 4) previously described are engaged by a cross bar 150 adjustably positioned at the upper end of vertically sliding rods 151 (Fig. 13). The rods 151 extend downward througlr bearing sleeves 152 (Fig. 3) and are provided at their lower ends with a cross head 154 having a cam roll 155 engaging a cam 156 on the intermittently rotated shaft 140.

The cam is so timed that the cross bar 150 and levers 106 will be raised during the lowering and feeding of the work table, thus raising the plungers 105 (Fig. 6) within the lapping spindles and withdrawing their tapered ends 104 from engagement with the lapping elements 90. As the table returns to operative position, the plungers or rods 105 are released and are allowed to move downward, under the pressure by the springs 110 (Fig. 4).

Timing mechcmz'sm 163, gearl64 and pinion 165 to the main drive shaft 37. The cam 160 is thus continuously rotated, but at greatly reduced speed.-

The cam 160 is preferably double-acting, asindicated in Fig. 16, and engages a cam roll 166 on the lower end of a bent lever 167, swinging on a fixed pivot 168. The lever 167 is slotted at 169 to receive a pin 170 in the side of an arm 171, having a feed pawl 172 (Fig. 17) at its outer end. The feed pawl 172 engages a ratchet wheel 173 loosely mounted on a stud 174 (Fig. 4) which also supports the arm 171. A

A holding pawl 175 (Fig. 17 is'mounted on an arm 176 also pivoted on the stud 174 and connected to a link 177 at its upper end. The link 177 is threaded to receive an adj usting nut 17 8 on the outside of the standard 33 and a spring 179 is mounted on the link 177 between a pin 180 on the link and a washer '181 engaging the inside of the casing 33.

An arm 183 (Fig. 17) is connected to move with the arm 17 6 about the axis of the stud 174 and is provided with a shield 184 which may be moved toward or away from the feed pawl 172 by adjustment of the nut 178.

As the feed pawl 17 2 has a constant stroke, the rate of feed may be varied by changing the position of the shield 184, so that more or less teeth on the ratchet will be uncovered for engagement on rearward movement of the feed pawl.

A lug or projection 185 is fixed on the side of the ratchet wheel 173 and is gradually advanced by the feeding of the ratchet until it engages a projection 187 (Fig. 16) projecting laterally from a rod 188 slidab-le in fixed bearings 189. The rod 188 extends freely through a collar 190 (Fig. 18) which is connected by a link 191 to an. arm 192 by, which a one-revolution clutch. of commercial form is controlled.

The normal position of the clutch parts is as shown in Fig. 19, in which a roll 193 is seated in the recess 194 of a fixed plate 195 and is also positioned in a similar recess 196 (Fig. 20) ofa second plate mounted for movement about the axis of the fixed plate 195 and having the arm 192 projecting therefrom.

The roll 193 is mounted on a lever 198 pivoted .at 199 on a split expanding band 200 surrounding the cylindrical hub 201 (Fig. 3) of the cam 160. Ashoulder 202 (Fig. 18) on the arm or lever 198 engages the end 203 of a.

notch or recess in a bolt 204 extending through an opening in the offset end 205 of the split band 200, said bolt having adjusting nuts 206 threaded thereon.

If the collar 190 (Fig. 18) is moved upward, it will act'through the link 191 to swing the arm 192 and its associated c-am plate about the axis of the clutch mechanism, bringing the recess 196 (Fig. 20) out of alignment with the recess 194, thus forcing the roll 193 outward, swinging the arm or lever 198 and tightening the spilt band 200 about the continuously rotating hub 201 of the cam 160.

The shaft 140 will thus be rotated for a single revolution, until'the notch 196 returns to alignment with the recess 194. Upon thus completing the revolution, the roll 193 will drop into the aligned recesses 194 and 196 and the shaft will again come to rest. The one-, revolution clutch mechanism above described in itself forms no part of my invention and any other suitable one-revolution clutch may be substituted therefor.

The collar 190 (Fig. 17 is loose on the rod 188 and is normally held from vertical move ment by a latch 210 mounted on a fixed pivot 211.. A spring 212 is mounted on the lower end of the rod 188 between the collar 190 and a pin 213 at the lower end of the rod.

When the projection 187 on the rod 188 is engaged by the. lug 185 on the ratchet wheel, the rod 188- is moved upward, compressing the spring 212, while the collar 190 remains locked by the latch 210. A cross pin 214 on the rod 188 eventually engages the latch 210, as the rod 188 reaches its upper position, thus unlocking'the collar 190 and allowing the same to slide quickly upward, swinging the arm 192' and rendering the one-revolution clutch operative.

will clear the projection 187 as the latch 210 is released, so that the rod 188 and collar 190 return to their normal lowered positions as shown in Fig. 17 before the single revolution of the shaft 140 has been completed. A weight 215 (Fig. 16) is provided to expedite the return movement and a handle 216 is provided for manual control of the clutch.

If it is desired to prolong the lapping operation, the shield 18 1s is moved upward by the adjusting nut 178 so that less teeth will be uncovered on the rearward movement of the feed pawl, and if it is desired to shorten the lapping operation, the shield is moved downward to uncover more teeth.

0 pe'ration Having thus described in detail the mechanism of my improved lap-ping machine, the general operation thereof is as follows The rings or collars or other similar pieces of work W arefirst mounted in the work holders 121 and one of these holders is aligned with the lap. The machine is then started in operation, rotating the lap 1 within the hole in the work and yieldingly forcing the lapping members 90 outward against the cylindrical inner wall of the work until the desired size and finish has been attained. The duration of the lapping operation is regulated by the setting of the shield 184 (Fig. 17) by the adjusting nut-178. At the end of a predetermined period, the one-revolution clutch is released and rotates the shaft 140 (Fig. 3) through a single complete revolution.

This rotation of the shaft 140 accomplishes several related purposes. In the first place, the cam 133 is rotated to lower the work table 40 away from the fixed guide roll 128. \At the same time, the cam 156 raises the expanding plungers 105 within the laps, allowing the lapping elements to contract during the lowering of the work table, and the presentation of 'a new piece of work. As the work table 40 approaches its lower position, the roll 145 engages one of the slots in the disc member 143, advancing the tab-1e 90. f

The cam 133 then returns the work table 40 to operative position and the cam 156 re leases the lap-expanding plungers. All of these movements are completed during the single revolution of the shaft 140, which comes to restas soon as the singlet revolution is completed. During this removal and replacement of the work, the lapping spindles 50--have continued to rotate and the slide plate 7 4; has con tinued its reciprocation, raising and lowering the laps in their usual manner.

The machine is thus entirely automatic in its operation and it is merely necessary for the workman to remove the finished pieces of -work and replace the same with new pieces the advantages thereof, I do not wish to be limited to the details herein disclosed otherwise than as set forth the claims, but what I claim is 1. In a lapping machine, a lapping spindle,

a lap comprising a plurality of depending lapping elements mounted on said spindle, automatically operated means to expand and contract said lapping elements, and a positive driving connection between said spindle and each lapping element.

2. A lapping machine comprising a lapping spindle, means to rotate said spindle, means to reciprocate said spindle, a lap comprising a plurality of depending lapping elements mounted on said spindle, automatically operated means to expand and contract said lapping elements during the spindle reciprocation, and a positive driving connection between the spindle and each lapping element.

3. A lapping machine comprising an expansible lap, mechanism arranged to rotate said lap, means to reciprocate said lap relative to and within a cylindrical internal work surface and automatically actuated means in;- dependent of the reciprocating means to yieldingly expand said reciprocating lap from an inoperative to an operative position after the lap has been entered into the work piece to be lapped.

4. A lappingmachine comprising an 1 synchronized with the reciprocating mechanism to expand said lap against a cylindrical internal surface to be lapped after it has been inserted within the work.

5. A lapping machine comprising an expansible lap, -a support for work having an internal cylindrical surface to be lapped, means to rotate said lap, mechanism to axially reciprocate the lap in operative contact within the work, and means to contract said lap and remove it from contact with the work surface after a predetermined number of lap reciprocations. v

6. An internal lapping machine comprising a lap, means to rotate said lap, means to axially reciprocate said lap relative to a piece of work having a cylindrical hole therein, automatic means synchronized with said reciprocating means to separate said lap and work after a pre-determined number of reciprocations of said lap, and means synchro-.

nized with said automatic means to automatically remove the work from lapping position and to present a new piece of work in lapping position.

In a lapping machine, a lap comprising a plurality of lappingelements, meansto rotaterand axially reciprocate said lap, a work holder, means to-cause said work holder and lap to approach and separate, and automatic ggeans synchronized with said last named eans to expand. said lap on an approach movement of said parts and to,contract said lapon a movement of separation of said parts.

. 8. A lapping machine comprisinga lap having a plurality of lapping elements, means to rotate and axially reciprocate said lap within a cylindrical internal work surface to be lapped, a work holder, means to cause said work holder and lap to approach and separate after a predetermined number 7 of lap reciprocations to withdraw the lap from the work, and means acting in synchronism with said last named means to'expand said lap on an approach of said parts and to contract the lap on a separation movement of said parts while the lap is withinv the work.

9. A lapping machine comprising an expansible lap, a support for work having an rocate the spindle, a lapping tool mounted upon one end of said spindle which is provided with expansible abrading elements, a

. cam rotatably mounted within the stationary frame, means to rotate the cam in timed relation with the spindle reciprocation, and connections between said cam and the expansible elements whereby they may be expanded and contracted at predetermined positions of said tool reciprocation and maintained in an expanded position for a predetermined number of tool reciprocations.

11. In 'a lapping machine, a lap comprising a plurality of lapping elements, means to rotate and axially reciprocate said lap, a work holder, means to cause said work holder and lap to approach, and to thereafter axially separateafter a predetermined number of reciprocations of said lap, and means synchronized with said last named means to expand said lap on an approach movement of said parts and to contract said lap on a movement of separation of said parts.

12, A lapping machine comprising an expansible lap, a work support, means to rotate the lap, means to axially reciprocate the lap within a cylindrical internal work surface, automatic mechanism to axially separate the lap from the work after a predetermined number of lap rotations, automatic means associated therewith and acting in timed relation with the lap reciprocation to expand the lap after insertion within the work and to contract the lap upon completion of a predetermined lapping cycle but prior to its removal from the work.

13. In a lapping machine, a lap comprising a plurality of lapping elements, means to rotate and axially reciprocate said lap, a work table, work holders thereon, means to cause said Work table and lap to approach, and to thereafter axially separate after a predetermined number of reciprocations of means actuated by said shaft to withdraw W said lap expanding means and permit the lap to contract, to axially separate said lap and work table, to angularly advance said table, and to thereafter restore said table and lap to operative relation and to expand said lap.

15. In a lapping machine, a lapping spindle having a grooved collar thereon, a lever engaging said collar, a slide plate, a link connecting said slide plate to said lever, spaced cam rolls on said slide plate, and a cam continuously rotating between said rolls to reciprocate said lapping spindle.

16. In a lapping spindle, means to rotate said spindle, means to reciprocate said spindle, a cap on the lower end of said spindle having an internal angular lower flange, a plurality of depending lapping elements each having an outer flange at its upper end cooperating with -said angular inner flange to attach said lapping elements to said spindle, means to prevent relative angular movement between said spindle and said lapping elements, and means synchronized with said rotating and reciprocating means to expand said elements. p

17. A lapping machine comprising a reciprocable member, a spindle rotatably mounted on said member, a lapping tool carried by the spindle and provided with expansible grinding elements, an expanding member therefor, and meansfor actuating the expanding member to maintain the grinding elements in operative engagement 7 and mechanism supported thereon so as to be reciprocable, a plurality of spindles r0.- tatably mounted in said mechanism, tools carried by said spindles provided with expansible grinding devices, control devices for said tools also carried by said spindles which hold said tools normally in collapsed position, means for independently operating said control devices, and mechanism for imparting movement to said last named means to cause a simultaneous expansion of all of said grinding devices during the operation of said first named mech'anism.

20. In combination with a stationary frame and frame mounted thereon so as to reciprocate, a spindle rotatable in said last-named frame, a grinding'tool on the end thereof, provided with expansible abrading elements, a rod in said spindle operatively connected with said abrading elements, a rocker-arm for engagement with said rod, means for imparting intermittent movements to said rocker-arm, to properly actuate said rod, and means for adjustment of the osition of said rod with reference to the roc er-arm.

Y 21. A lapping machine comprising a main frame and mechanism supported thereon, a plurality of spindles mounted for simu1taneous rotation and reciprocation by said mechanism, tools carried by said spindles provided with expansible lapping members, control devices for said tools carried by the spindles, means acting in timed relation with the tool reciprocation to maintain said tools in a collapsed position when withdrawn from the work and to expand the tools into contact with the work after insertion therein, and yielding means cooperating therewith to cause an expansion of the laps as the lapping operation proceeds.

22. A lapping machine comprising a staarm arranged to engage said rod, mechanism acting in timed relation with the spindle reciprocation for imparting cyclic movement to the rocker arm and thereby positioning each of the abrading members in positive engagement with the internal work surface during a predetermined number of spindle reciprocations, and means for adjusting the position'of said rod relative to the rocker arm.

23. In combination with a main frame and mechanism supported thereon so as to be reciprocable, a plurality of spindles rotatably mounted in said mechanism, tools carried by 'said spindles, provided with expansible grinding devices, control devices for said tools, also carried by said spindles, holding said tools normally in collapsed. position, means for the independent operation of said control devices, and mechanism for imparting movement to said last-named means to cause a gradual expansion of all of said tools dur ing the operation of said first-named mechanism, and means for withdrawing said expanding member to permit the collapse of said grmding elements at the end of said pre-determined number of reciprocations.

24. In a honing machine, the combination of anexpansible honing tool, means for rotating said tool, means for shifting said tool into and out of the work and for reciprocating said tool within the work, means for ex- 7 panding and contracting said tool, and means automatically operable during the shifting of said tool to actuate said last named means to thereby free said tool from the work during insertion and extraction therefrom.

25. In a honing machine, the combination of an expansible honing tool, means for rotating said tool, means for shifting saidtool into and out of the work and for reciprocating said tool within the work, means for ex-' panding and contracting said tool, and cam controlled means automatically operable during the shifting of said tool to actuate said last named means.

In testimony whereof I have hereunto affixed my signature.

HERBERT S. INDGE.

tionary frame, a support mounted thereon so as to reciprocate, a spindle rotatably mounted in said frame and arranged to reciprocate with said support, an expansible grindin tool fastened to one end of the spindle and provided with radially movable abrading members, an axially movable rod within said 

